In our efforts to identify gene products important to the pre-tRNA splicing process, we discovered unanticipated categories of proteins that are likely to play a role in the regulation and subcellular location of the splicing enzymes and the pre-tRNA substrates, as well as a protein that is likely to interact with the pre-tRNAs. Our studies of RNA1 and SRN1 link environmental stimuli (i.e., glucose) and RNA processing. Our studies of RNA1 and SFP1 link nuclear import or nuclear structure and RNA processing. Our studies of LOS1 indicate that proteins of the nuclear membrane can affect pre-tRNA processing and our studies of Stp1p provide evidence for the role of accessory proteins for the catalytic steps of pre-tRNA splicing. The proposed work is designed to critically define the steps at which each of these gene products functions and to determine the macromolecules with which they interact and consist of five specific aims. These are to: (A) confirm that RNA processing responds to glucose and study the mechanism(s) by which this environmental signal is transmitted to the RNA processing machinery; (B) investigate how nuclear-cytosol communication is involved with RNA processing; (C) continue studying RNA1 and its proposed central role in coordinating environmental stimuli, nuclear-cytosol communication and RNA processing; (D) determine whether Los1p affects the topology of splicing endonuclease in the nuclear membrane; and (E) test the model that Stp1p can affect pre-tRNA-splicing endonuclease interaction.